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Diamond Buying Guide

The Art of Diamond Cutting

​​​​​​​​​​​​​​​​​​​​​​​​​​Diamond Cut

Diamond Buying GuideThe key to the beauty of diamond, it’s very heart and soul, is light. Its ability to alter, bend, and manipulate whatever light it might be exposed to is what makes diamond so unique.
Cutting standard, how the diamond is transformed from the rough diamond crystal into the finished, polished gemstone that you see in a piece of fine jewelry, such as an engagement ring, is the single most important factor of all in determining how a diamond will deal with light. There are several reasons for this.
Mother Nature gifted diamonds with a truly unique, wonderful, collection of physical and optical traits, abilities, and potentials which, if applied correctly, will result in dazzlingly beautiful diamonds that Mother Nature is very proud of because they are reaching their maximum potentials for beauty. Those potentials are entirely dependent upon how accurately a diamond is cut and polished into its final form. Mother Nature left that decision up to us!
Simply stated, if cut properly, a diamond will be absolutely, breathtakingly, beautiful. If not cut and polished correctly, it will not reach its potentials and the differences will be noticeable even to the untrained eye.
“Cut” also determines what a diamond will weigh when the cutting procedure is completed. As diamonds have been bought and sold on a weight basis for untold centuries, this is obviously a very important factor from a value standpoint. A diamond’s weight (discussed in greater detail under the “Carat Weight” category below) is also a convenient way to discuss or categorize diamonds.
Diamond cutters must make many, many vital decisions when determining how to cut a diamond crystal.
First, they must determine what is most important to them: beauty or finished weight. A simple fact of life is that if a cutter desires the most beautiful diamond possible, weight must be sacrificed in order to achieve that beauty factor. There is no escaping that fact. As a result, some diamond cutters, for purely philosophical or personal reasons, only cut their diamonds to the very most stringent of standards…truly fanatical accuracy and with truly spectacularly beautiful results! Other cutters might have a different take on the subject or a different skill level, technical expertise level, or business model or target market. They might choose to cut their diamonds simply to be a big and cheap as possible and beauty really doesn’t matter to them. Many cutters choose to be somewhere in between and offer a very wide assortment of cutting standards and value ranges.
Secondly, diamond cutters can’t just start cutting away any way they please; they must carefully analyze each diamond crystal to determine what it will or will not allow the cutter to do with it! Some diamond crystals only provide the cutter with one choice or there might be many, many options for any given diamond crystal. Only a highly skilled individual can inspect a rough diamond crystal and determine what potentials are hidden inside just waiting to be released. Extraordinarily large, rare, crystals are commonly studied for many months, even years, by teams of experts, before the final cutting decisions are made.
Once the cutters understand what the crystal is telling them, they can then decide upon the final shape of the finish diamond, or diamonds, which can be cut from the crystal. Once the final decisions are made, and the cutting process is started, there is no turning back! As diamond is the very hardest substance that Mother Nature has ever devised, cutting it is a real challenge requiring enormous skill, experience, training, and complex equipment. Diamond crystals have a “grain” or “structure” (much like the wood that is used to produce fine furniture) that puts great limitations upon the cutters. But, if everything is done correctly, and the diamond crystal has been dealt with properly, the end product will be fabulous!
Discussing “cut” is a process, not an event! The complexity of this subject can be daunting (or really boring & scary, depending upon one’s outlook!) as it requires delving into subjects such as general physics, optical physics, mineralogy, chemistry, geometry, mathematics, engineering and so forth. But…it can also be a fascinating and extremely interesting subject if explained properly, which can be done without getting overly technical. In fact, learning about “cut” can be really fun. And, remember, it is the heart and soul of diamond’s beauty!
In general, simple terms, a diamond is cut with many planes or “facets” on its surface, both top and bottom, and commonly around the edge as well. Each facet has a specific purpose or job, so to speak, and they work together as a team to manipulate whatever light the diamond can collect. If a diamond’s facets are cut at the proper angles, sizes, shapes, and relationships, relative to one another, and polished to a perfectly smooth surface, diamond has the ability to catch or collect light, bend it, toy with it, change its directions and shoot it back at the viewer in a way that transforms that light into a spectacular mix of the spectral or rainbow colors and flashes of white light.
Different shapes of diamonds (round, oval, marquise, pear shaped etc) require different combinations of facet sizes, shapes, and angles. Different variants of cutting standards can produce different effects, even within a given shape or outline. Some people might find one “look” more attractive than others while other people might be drawn to a completely different “look” altogether. That is why it is absolutely necessary for a potential buyer to actually see, in person, any diamond that might be considered. A little experience will go a long way when it comes to recognizing if a diamond is cut well and if it is beautiful or not!
A diamond can generally be described as having three major physical components, the crown, the pavilion and the girdle. Below is a general description of the basic parts of a diamond and a simple diagram to demonstrate the basic outline of a round brilliant cut diamond.
The crown, or “top”, of the diamond, is made up of facets that act primarily as windows and prisms. The big flat facet on the very top is called the table. The other facets to the side of the table are referred to bezel or crown facets, star facets, and upper girdle facets.
The “bottom” of the diamond is known as the pavilion and its facets act primarily as mirrors. The extremely small facet (or sharp point) right in the middle of the pavilion is known as the culet. The long, spear-like facets are called the pavilion main facets and the pairs of triangular facets are called the lower girdle facets.
The edge that extends all the way around the diamond, where the crown and pavilion meet, is known as the girdle. Its main function is to act as a place that allows the diamond to be griped and secured into a setting of some sort and to provide a connecting base or foundation for both crown and pavilion.​

A simplified explanation of how light moves inside a diamond

Diamond Buying GuideThe crown facets and table, acting as windows, collect light from every possible angle, from the girdle to directly overhead and they allow light to enter into the body of the diamond. Then, in turn, the light bounces off of the pavilion facets and reflects in different directions. If the diamond is cut correctly, the light will bounce off of other pavilion facets and turn yet again and be redirected back towards the crown from the inside. Essentially, the light does a U-turn inside the diamond! When the light strikes the crown facets from the inside (and exits the diamond) the crown facets take on the role of prisms, and break up that light into a splash of spectral/rainbow flashes of color flashes mixed with bright flashes of white light as well. This is demonstrated by the middle example in the diagram to the right.
Diamond Buying GuideIf the diamond is cut too steeply (deep), it cannot manipulate light correctly and efficiently and much of the light is lost or used improperly. The same thing happens if the diamond is cut too flat (shallow). Either way, light is lost, the diamond is not optically efficient, and its beauty is diminished accordingly. This is demonstrated in the two diagrams.​
There are many terms used to describe cutting standards. The term “ideal” is commonly used within the fine jewelry industry but, unfortunately, it is badly abused. At Erica’s Fine Jewelry our goal is for you to understand this subject extremely well. We would invite you to contact us for a more complete description and discussion on this topic so that you can fully understand terms such as “Ideal” used generically, “Tolkowsky Ideal”, “American Gem Society, or AGS, Ideal” and so forth. Your understanding of this vital subject will help make your decision making process much more enjoyable and successful.
Cutting quality is the single most important and volatile of the 4 Cs relative to how it affects both beauty and value. You can take diamonds that are essentially identical when it comes to all the other factors, but varying cutting standards can cause fluctuations in price of 50% or more! It is why diamonds, that sound the same on paper, can look completely different to you and have radically different values associated with them.​
​Cut grading terminology varies widely from laboratory to laboratory and jeweler to jeweler. Although it is absolutely the most important “C”, it is, by far, the least understood factor and the one that many jewelers choose to avoid discussing with their clients. That is simply wrong morally, ethically, and professionally. Truly professional jewelers will gladly help you to understand this most important of subjects.
The Gemological Institute of America uses a descriptive terminology that is broken up into five categories: Excellent, Very Good, Good, Fair and Poor.
The American Gem Society uses a 0-10 scale with “0” being the best possible and “10” being the worst possible grades.
These are the two most often encountered Cut Grade Systems and it is worthwhile for you to understand both as they develop their grades using somewhat differing technologies and scientific disciplines.

For a truly comprehensive discussion of the fascinating topic of “cut” we would invite you to come into Erica’s Fine Jewelry, or contact us via phone or email, and allow us to demonstrate to you why this topic is so very important when it comes to choosing the perfect diamond.​